When my washing machine drains it sometimes comes up and out of the open pvc pipe in the service closet where the water heater would drain. I've found lots of posts where people speak of the washer standpipe overflowing, but can't find any info on what would cause my problem. When the washer drains I have to stand at the service closet (next to each other in the garage) and watch/listen. First I can hear gurgling, then hear the water coming up the pipe (similar to the sound of filling a glass of water), then I can see the water just before it emerges and floods my service closet and garage. If I turn the washer off and on as it drains this doesn't happen...but not really feasible for the long run. Any ideas?

11 Answers 11


It sounds like the pipe is partially blocked and water can only get through at a slower speed. The drain at the hot water is the lowest point so that's why it is coming from there. The blockage could be anything, from debris that came in through the pipe in the service closet or a sock that made it out of the washer. Since it's after where the water is coming out of the service closet then you might be able to get a drain snake the problem but you might have to get an expert to get it cleaned out.


lqlarry is likely right, and using a snake to clean out the line is the first step. (+1 Larry)

It could also be a problem with the plumbing vent. If that is the issue, you would likely hear a gurgle after you shutoff the washing machine and the water gets down to the P-trap, not unlike the sound the toilet makes at the end of the flush.

The other issue I can think of is that the plumbing drain is improperly sized or sloped. If that's the case, this problem would have always happened, and wouldn't be a new issue.

  • Thanks for your responses. BMitch, it does gurgle, so that's good to know. I just bought the house so I don't know it's plumbing history. The home warranty people sent a plumber out who tried to snake it from the service closet, but he said it had a drum trap in the line instead of a P trap and he couldn't (?). I had another plumbing company come out last week and they thought the drain line is too small and too short. They're coming tomorrow to dig an outdoor cleanout as I have a problem with the back bathroom, but I'm unsure what to do about this issue. This second plumber wants me to file a
    – Carey
    Commented Feb 19, 2012 at 21:25

We hooked up water hose to a stopper from Ace. It kept water from coming back and force washed the clog out. I did use liquid Plumber followed w/hot water first. The clog looked like big pieces of dried washing powder.

  • 1
    Could you add a link to the stopper you used?
    – Niall C.
    Commented Jun 30, 2013 at 13:25

Think air behind water. The drain must be properly vented for it to withstand the rush of water from a washing machine pump.


If the washer drains into a dry well, then the dry well is probably clogged with lint. You will have to dig it out or dig a new one. We had that problem at my son's house.


It's because the water flows out faster than the pipe can drain. The easiest way to fix this is to seal up the washing machine waste hose against the open PVC pipe. Some gaffer tape should do the trick.

Otherwise you could fit a holding tank above the drain which is allowed to fill and provides time enough for it to drain out without overflowing.

A harder option would be to increase the size of the waste pipe so that it can take a larger volume of water through it.

  • Matt's right. I've lived in two separate houses with this same issues. Washers today drain at higher volumes than their predecessors in years past. Will try all ideas this time. But, last time, I recall using a fire hose to drain to the ditch... not a great idea, but what to do? what to do?
    – user15094
    Commented Sep 14, 2013 at 19:43
  • 1
    This is not a great idea because turning the drain pipe into a pressurized system rather than one with an air gap will create a siphon that will cause the washer to never stop draining once it starts and there is still water in the tub. This will obviously waste a huge amount of water, but it could also burn out the pump and cause a flood anyway as there's simply only so much water the pipe can accommodate. Start by snaking it and go from there.
    – iLikeDirt
    Commented Apr 22, 2014 at 13:55
  • iLikeDirt - Pressure equalisation comes from the air inside the washing machine. There is no siphon. I've had to do the seal method and it worked but was done temporarily. It didn't cause any problems at all and it indeed did drain.
    – hookenz
    Commented Apr 22, 2014 at 21:51
  • That's true, as long as the machine isn't filling at the same time. Anytime it's both draining and filling, you'll get a siphon.
    – iLikeDirt
    Commented Apr 22, 2014 at 21:54
  • @iLikeDirt unfortunately due to bad old plumbing in my house i have to seal my house on to my drain. It usually works ok but sometimes it won't fill. Until i can fix the plumbing issue ( which I've traced to underneath the slab in my bathroom) what would you suggest i do to have it work consistently?
    – user6591
    Commented Aug 25, 2016 at 13:50

I only had that problem when I purchased a newer washer. I purchased a rubber piece from a hardware store, it came with two clamps that goes around each end. One end goes over the pipe and the other end goes over the rubber pipe to the washer. Tighten the clamps. No more problems with water backing out because of the tight seal. It didn't cost a lot and I didn't have to call a plumber which would have cost money and the problem not fixed.

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    What was this rubber piece called? Can you provide a link?
    – Niall C.
    Commented Nov 4, 2013 at 1:44

Get the washer drain piping snaked out. Have the plumber run down the vent stack for the washing machine. This should take care of your problem.


The end of drain hose is too deep down to the standpipe, it chokes. It should extend no more than 4" from the finishing end of the upside down U handle.


I had the same problem with a new washer overflowing an old drain pipe. Tried snaking it, Drano-ing it, and plundgering it but no luck - it still would not drain fast enough to keep up with the washer. This pipe was very old and runs under the house, so way too much work to try and increase its flow rate any more invasive other way.

So I ended up reducing the flow rate of the drain hose from the washer by inserting a section of vinyl hose into it. Costs about $5 at the hardware store. I iteratively added flow-reducing notches to the hose until the rate was right.

It has been several months and while the washer now takes a little longer to cycle, it has not overflowed again. enter image description here enter image description here


Firstly I'd make my best attempt at ensuring the drain line is clear. A basic handheld auger is relativity inexpensive at any box HW store and a worthwhile homeowner investment regardless. Other issues could be too many elbows or pipe is just undersized. Drain should use 1-1/2" pipe, utilizing a P-trap as well.

But if that all checks out or re-piping would be impractical a simple cheap modification would be to just install a 3/4" PCV coupling (Actual ID is 1") into the washer's drain piping. Ideally from under the washer, not in the flex drain hose itself. The intermediate connection between the washer and drain hose is usually 1-1/8". That connection will block the coupling from flowing past while providing a minimal restriction, slowing the flow only as much as is necessary.

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